1. Definition of Terms
A) Internal combustion engines: in general refers to engines that naturally aspirate with a throttle valve controlling and restricting the air flow through the intake manifold and where fuel does not partake in a lubricant function.
B) Any fuel delivery system, for example, carburetor, throttle body injection continuous injection system, multipoint injection, pulsed electronic fuel injection, mixer dosifier of air for natural gas or liquid petroleum gas, diesel direct injection.
C) Any fuel: refers mainly to fuels inflammable by a spark of ignition, such as: gasoline, methanol, ethanol, or gasohol mixtures, natural gas, liquid petroleum gas. In case of any reference to diesel or fuel-oil, we will refer specifically to them.
2. Background Discussion
It is common knowledge that for a conventional combustion engine, the ideal combustion could be defined by the relation between: the maximum amount of energy generated by the minimum amount of fuel mixed with the exact amount of oxygen present in the air-fuel mixture, uniformly distributed in each cylinder to produce the total burning of fuel, while a minimum production of solid residues and polluting emission results. This definition would represent reaching almost 100% efficiency in a combustion process. For the purpose of reaching maximum efficiency and a significant reduction of fuel consumed by internal combustion engines, it is convenient to discriminate the main factors involved in the combustion process as well as the problems and limitations of operational design inherent to engines and how it affects their internal combustion and performance.
3. Oxygen, Essential Factor
In order to burn fuel and for combustion to take place, it is necessary for a carburetant to be present. Specifically, the carburetant is oxygen, which is an indispensable element for enabling combustion to take place. Combustion is an oxidation process where the elements carbon and hydrogen present in the oxidation reaction provide high energy production and harmless byproducts (carbon dioxide and water).
RICH CONDITION--If we work with an excess of fuel and there is not enough oxygen to burn all the fuel, it will result in certain portions of uncombusted fuel, which will form carbon deposits in the combustion chamber and highly toxic emissions such as residual hydrocarbons and carbon monoxide expelled to the environment through the exhaust system. Also, engines will consume a greater amount of inefficient fuel wasted in producing harmful byproducts and not in generating energy.
LEAN CONDITION--Due to the fact that all the oxygen used in internal combustion engines is supplied by atmospheric air with the inconvenience that air can only supply approximately 20% of oxygen together with an unwanted 80% of nitrogen, it would be reasonable to supply excess of air to burn all the fuel entering the combustion chamber. But, the problem is that excess air generates high combustion temperatures and both elements nitrogen and oxygen combine, thereby forming nitrogen oxides (NOx emissions) which are harmful byproducts, key element of smog. Both working conditions (rich and lean) produce harmful emissions contributing to smog formation, in contrast to the clean air desired.
STOICHIOMETRIC RATIO
For today's engines, with the increased emphasis on fuel economy and reduced emissions, the air-fuel ratio has to be controlled much more carefully. The ideal air-fuel ratio, the one which yields the most complete combustion and the best compromise between rich and lean mixtures is 14.7:1, the mixture is neither rich nor lean, this ratio is expressed in terms of mass. Modern technologies and vehicle manufacturers express that the stoichiometric ratio can also be described in terms of the air requirements of engines, and calls this, the `EXCESS AIR FACTOR` or LAMBDA. At the Stoichiometric Ratio, when the amount of air equals the amount required for complete combustion of fuel and there is no EXCESS AIR-Lambda=1. When there is excess air (air-fuel ratio leaner than stoichiometric) Lambda will be greater than one. When there is a shortage of air (air-fuel ratio richer than stoichiometric) then Lambda will be less than one. This concept of Lambda (the excess air factor) was created to support thinking in terms of the air requirements of engines working with electronic fuel injection where intake air-mass flow is measured and a computer determines the corresponding amount of fuel to be injected. Older carburetor systems tend to run richer than the ideal air-fuel ratio, where air flow through carburetors extracts proportional amounts of fuel from venturis. In other words, every time the term "Air" appears in this application, it should be understood, which way and how much oxygen is supplied to the engine and possible harmful byproducts affecting emissions.
LIMITATIONS OF THE OPERATIONAL DESIGN
This concerns, restrictions and inconveniences related to engine design that affect negatively the appropriate supply of "Air" for the combustion process promoting incomplete combustion and affecting regulated emissions. Main Limitation--It is well known that in carbureted and throttle body injected (Central Injection) engines, the fuel and the air, are supplied together by the fuel delivery system, where the vacuum low pressure is responsible for the aspiration and formation of an air flow drawn from the ambient (at atmospheric pressure). This intake air flow will receive the intake atomized fuel (from venturis or fuel injectors) in order to transport it, mixed in the air current running through the intake manifold for its later ignition at the combustion chamber. In multipoint fuel injection (Ported Injection) fuel is sprayed by injectors at ports located into the intake manifold very near to the intake valves. For both cases, older and latest fuel delivery systems, the main limitation is the throttle valve controls that restrict the unique air supply. This joint supply of fuel and restricted air creates an inconvenient interdependence between them, which in the end translates into limitations imputable not only to the design, but also to the way the engine performs and the way the fuel delivery system operates under different throttle positions and vacuum variables, generating problems such as: defective vaporization and adherence of liquid fuel to elbows, walls, and ports of the intake manifold; irregular distribution of air-fuel mixture to each of cylinders; rich or lean mixtures under different operational conditions. All these problems translate into partial burning of fuel resulting in certain portions of uncombusted fuel wasted in producing harmful byproducts. Furthermore, for carbureted engines it is impossible to increase the air flow, taken in through the fuel delivery system, without producing simultaneously extraction and aspiration of an additional amount of fuel. Consequently, this explains the inconvenient interdependence resulting from a joint supply of air and fuel, as well as removing the possibility of supplying additional air by restricted normal intake. On the other hand, in order to reduce the fuel consumption, obviously the amount of fuel delivered should be reduced. To manage this, we must reduce the diameter of the passages located at internal parts (gillets, venturis, or injectors), through which the fuel runs in the fuel delivery system, or shorten the pulse time (Electronic Injection). Such a reduction could be so noticeable, that it would be very easy to find the proper amount of restricted air to match and carry out the combustion of all the reduced amount of fuel, with a minimum production of residues and effluents, but also, energy excepted by explosion will be reduced, thus generating less power. From the above we can derive that a reduction of fuel `per se`, implies a sacrifice in the power of the engine. Such problems and limitations just mentioned are subject to corrections and improvements, this is one of the objectives of this invention.